 default namespace lib = "http://eric.van-der-vlist.com/ns/library"
 namespace local = ""
 namespace inh = inherit
 namespace hr = "http://eric.van-der-vlist.com/ns/person"
 
 start = element library { book-element+ }
 
 anything = ( element * { anything } | attribute * { text } | text )*
 
 foreign-elements = element * - (local:* | lib:* | hr:*) { anything }*
 
 foreign-attributes = attribute * - (local:* | lib:* | hr:*) { text }*
 
 foreign-nodes = ( foreign-attributes | foreign-elements )*
 
 author-element = 
    element hr:author
    {
       attribute id { text },
       name-element,
       born-element,
       dead-element?
    }
 
 book-element = 
    element book
    {
       attribute id { text },
       attribute available { text },
       isbn-element,
       title-element,
       foreign-nodes,
       author-element*,
       character-element*
    }
 
 born-element = element hr:born { text }
 
 character-element = 
    element character
    {
       attribute id { text },
       name-element,
       born-element,
       qualification-element
    }
 
 dead-element = element hr:dead { text }
 
 isbn-element = element isbn { text }
 
 name-element = element hr:name { text }
 
 qualification-element = element qualification { text }
 
 title-element = element title { attribute xml:lang { text }, text }
